Flotation of sulfide ores

ABSTRACT

An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity of a flotation collector corresponding to the formula WHEREIN A is a radical corresponding to the formula   D R A W I N G

United States Patent [72] Inventors Guy H. Harris Concord, Calii.; Terry D. Filer, Idaho Falls, Idaho [21] AppLNo 799,071 [22] Filed Feb. 13,1969 [45] Patented .luly6,1971 [73] Assignee The Dow Chemical Company Midland, Mich.

[541 FLOTATION 0F SULFlDE ORES 8 Claims, No Drawings [52] U.S.Cl 209/166, 260/327, 260/3409, 260/455 [51) lnt.Cl B03d1/00, C07c153/00 [50] FieldolSearch 209/166, 167; 260/455, 327, 340.9

[56] References Cited UNFI' ED STATES PATENTS 2,342,332 2/1944 Dean 260/455X 2,691,635 10/1954 Harris... 209/166X 2,701,253 2/1955 Jones 260/327 2,895,980 7/1959 Harman 260/455 3,025,214 3/1962 Eden 260/327X 3,082,237 3/1963 Damico 260/455 3,464,551 9/1969 Falvey 209/166 3,290,351 12/1966 McKay 260/455 FOREIGN PATENTS 1,032,733 6/1958 Germany 260/455 Primary Examiner-Frank W1 Lutter Assistant Exam iner- Robert Halper Attorneys-Griswold and Burdick, William R. Norris and Bruce M. Kanuch ABSTRACT: An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity ofa flotation collector corresponding to the formula wherein A is a radical corresponding to the formula X and Y consist of S- or -O; R, R and R are hydrocarbyl groups, R, is an alkylene group and R is H or a lower alkyl group. Certain of the indicated compounds provide for enhanced selectivity and/or recovery of sulfide minerals of Cu, Zn, Mo, Co, Ni and Pb over iron sulfide.

FLOTATION OF SULFIDE ORES BACKGROUND Flotation is a process of treating a mixture of finely divided mineral solids, e.g. a pulverulent ore, suspended in a liquid whereby a portion of such solids are separated from other finely divided mineral solids e.g. clays and the like materials present in the ore, by introducing a gas into the liquid (or providing a gas in situ) to produce a froth mass containing certain of the solids on the top of the liquid, and leaving suspended (unfrothed) other solid components of the ore. Flotation is based on the principle that introducing a gas into a liquid containing solid particles of different materials suspended therein causes adherence of some gas to certain suspended solids and not to others and makes the particles having the gas thus adhered thereto lighter than the liquid. Accordingly, they rise to the top of the liquid to form a froth.

Various flotation agents have been admixed with the suspension to improve the frothing process. Such added agents are classed according to the function to be performed: Collectors, e.g. high carbon chain compounds such as collectors for sulfide minerals including xanthates, thionocarbamates, and the like; frothers which impart the property of forming a stable froth, e.g. natural oils such as pine oil and eucalyptus oil; modifiers such as activators to induce flotation in the presence of a collector, e.g. copper sulfate; depressants, e.g. sodium cyanide, which tend to prevent a collector from functioning as such on a certain mineral which it is desired to retain in the liquid, and thereby discourage a substance from being carried up and forming a part of the froth; pH regulators to produce optimum metallurgical results, e.g. lime, soda ash, and the like.

It is of importance to bear in mind that additaments of the above type are selected for use according to the nature of the ore, the mineral sought to be recovered, and the other additaments which are to be used in combination therewith.

An understanding of the phenomena which makes flotation a particularly valuable industrial operation is not essential to the practice of the present invention. They appear, however, to be largely associated with selective affinity of the surface of particulated solids, suspended in a liquid containing entrapped gas, for the liquid on one hand and the gas on the other.

The flotation principle is applied in a number of mineral separation processes among which is the selective separation of such minerals as sulfide copper minerals, sulfide zinc minerals, sulfide molybdenum minerals and others from sulfide iron minerals. The present invention concerns a novel class of compounds. These unique compounds can be used as collection agents in a flotation process. With some of the compounds better recoveries are realized and with others improved selectivity is achieved. Certain of the novel compounds produce an improvement in both aspects.

DESCRIPTION OF THE lNVENTION The novel compounds of the present invention correspond to the general formula wherein a. R is an alkylene group containing up to about carbon atoms, preferably up to about 5 carbon atoms;

b. R is a hydrocarbyl group, other than an aryl group wherein an atom in the ring structure is bonded directly to Y,

c. Y is -S- or -O-; and

d. A is a radical corresponding to the formula wherein i. R is H or a lower alkyl group containing up to about 7 carbon atoms and preferably up to about 3 carbon atoms; and

ii. when R; is an alkyl group, X and X are both -S- or -O-;

iii. when X and X are both -O- and R is a lower alkyl group, R and R are independently an alkyl, alkenyl, cycloalkyl or cycloalkenyl group containing up to about 7 carbon atoms and preferably up to 3 carbon atoms;

iv. when X and X are both -S- and R is a lower alkyl group, R and R are the same alkyl, alkenyl, cycloalkyl or cycloalkenyl group containing up to about 7 carbon atoms and preferably up to about 3 carbon atoms;

v. when R is H, X and X are independently -S- or -O- and R and R' are independently an alkyl, alkenyl, cycloalkyl or cycloalkenyl group containing up to about 7 carbon atoms and preferably up to 3 carbon atoms;

or (2) A is a radical corresponding to the formula wherein X and-X are independently -O- or -S-; R and R are independently H, or an alkyl group containing up to about 5 carbon atoms and preferably up to about 3 carbon atoms, and R is H or an alkyl group containing up to 7 carbon atoms, preferably up to 3 carbon atoms.

Preferably R, is a member selected from the group consisting of an alkyl or alkenyl group containing up to 18 carbon atoms, preferably up to about 10 carbons; a cycloalkyl, or cycloalkenyl group containing up to about 8 carbon atoms, or an aralkenyl or aralkyl group wherein the alkyl or alkenyl portion contains up to about 5 carbon atoms and is bonded to Y.

The novel compounds can be prepared, for example, by reacting an aminoacetal, aminoketal, aminothioacetal or aminothioketal compound corresponding to the formula,

wherein R, R, X, X, R, and R are the same as defined hereinbefore, with a xanthate ester corresponding to the formula s BJ'T T T T J wherein R is the same as defined hereinbefore and R., is usually a lower alkyl group such as methyl or ethyl. A mercaptan R,SH is evolved during the reaction.

The compounds as defined herein are particularly suitable for use in standard flotation processes as flotation collectors to concentrate copper sulfide and other like minerals from sulfide ores. In such processes a pulp is first prepared by wet grinding theore to a suitable size with or without a pH modifier. A suitable frothing agent is then added, e.g., pine oil. cresylic acid, polyalkoxyparaffin and the like. An effective quantity of a compound as defined herein is then added, preferably ranging from about 0.0l lb. to about 0.25 lb. per ton of pulp and the pulp is then agitated and aerated. The copper minerals and other like sulfide minerals collect as a froth which is readily overflowed or skimmed off from the residual gangue and nondesired materials and the metal values therein recovered.

The following Examples will facilitate a more complete understanding of the present invention but they are not meant to limit the scope of the invention to the specific embodiments incorporated therein.

Example 1 One species of a compound within the scope of the present invention and corresponding to the formula S CH;

CH1CH(CH3);

was prepared in the following manner.

To 19.2 grams of (l-Bu) CHaCH-O-t'L-SCH;

was added 13.3 grams of H,N-CH -CH(OC H The reaction was warmed on the steam bath to 60 C. CH SH was evolved. Heating was continued under a reduced pressure of 30 mm. until CH SH ceased to be evolved. The yield was 94 percent. The product was subjected to infrared and NMR analysis, said analysis confirming the structure set forth directly above. Example 2 Another compound within the scope of the present invention corresponding to the formula was prepared in the following manner:

In a manner similar to that described in Example 1, 13.2 grams of distilled E@ Q I&:$. was reacted with l 1.7 grams of H,NCH,CH(OC H A 90 percent yield of product was obtained. The structure of the compound set forth above was confirmed for the product by infrared and NMR analysis. Partial calculated analysis for the compound is 052.98 percent, H-9.00 percent and N-5.95 percent. Actual partial analysis of the product obtained was C-50.6 percent, H-8.5 percent and N-6.3 percent. Example 3 Another compound within the scope of the present invention, corresponding to the formula was prepared in the following manner. To 138 grams of dimethyl trithiocarbonate was added 16.1 grams of the diethyl acetal of 4-aminobutanal. The temperature of the reaction mixture rose to about 50 C. with the evolution ofCl-l sl-l. The reaction was completed by heating the mixture at a temperature of from about to C. under a reduced pressure of about 30 mm. until CH SH was no longer evolved. The product was an oil, obtained in about 92 percent yield. The above assigned structure for the compound was confirmed by infrared and NMR analysis.

Other species of compounds within the scope of the present invention were prepared in a manner similar to that defined in the previous examples. The compounds corresponded to the following formula:

(CH3CHZO)2CH(CHZ)3NI J; 0CHZCH3 Calculated partial analysis is C-52.98 percent, H-9.30 percent and N-5.62 percent. Actual partial analysis of the prepared product was C-52.8 percent, H-9.3 percent and N- S.5 percent;

(CH O)2CHCH NHii-O CBHIB and S l (CHaOhCH CH NH-OCH CH was employed as a control.

An ore sample was ground for 5 minutes at a pulp density of 59 percent solids together with 0.6 lb./t0n of lime. The pulp was then diluted and conditioned for 2 minutes with the indicated amount of a collector compound, listed. in Table l, and

0.088 lb./ton of frother. The pH of the pulp was 9.4. Flotation was then carried out for 8 minutes. The concentrate and 1115 I; s tailings obtained were dried and assayed. The results obtained, E thehcotl lelftor co in aurlids and amount employed are set forth 1 e 0 CW1 a e CZHJO 55 n t ng TABLE I Lbs/ton Percent Cu Run Number Collector compound added recovered O. 016 81. 1 0. 032 82. 1 0. 82.8 0. 240 83. 5 i 1 (C2H O)2CHCH2NHCOCHCHzCH(CH3)2 0.160 81.0

CH: 2 (CgH O)2CH(CH2) NHfiOCHQCHa 0.016 83. 2

S 3 Same as above 0.032 80. 4 4 .do 0. 160 81. 4

ll 5 (C2H50)2CHCH2NHCOCH(CHZ)2 0.160 81. 4

o Same as above 0. 240 83. 2

ll 7 (C2H O)2CH(CH2)3NHCSCH3 0.016 81.0

8 Same as above 0. 032 82.5

Cyclic aminoacetals useful in preparing compounds within the scope of the present invention can be prepared by a number of procedures known in the organic synthesis art. For example potassium phthalimide can be reacted with an achloro (or a-bromo) carboxylic acid to form a compound corresponding to the formula This compound can then be contacted with thionyl chloride and a base to provide a compound corresponding to the formula C ll 0 After this compound is purified it is reduced by the Rosenmund method with hydrogen over a regulated Pd catalyst at the lowest temperatures at which HCl evolves to form the corresponding aldehyde. The aldehyde is condensed in the presence of SnCl with an alkylene oxide,

in an anhydrous solvent to give a compound corresponding to the formula wherein R is H. Treatment with hydrazine gives the cyclic aminoacetal corresponding to the formula wherein R, R and R are the same as defined hereinbefore and R is H.

Cyclic aminoketals i.e. compounds corresponding to the general formula manner. A chloro or bromo ketone is reacted with a phthalimide salt. The product is condensed in the presence of SnCl ing product treated with hydrazine to produce the cyclic aminoketal. The sequence of the reaction steps can be suinmarized as follows Other cyclic species can be prepared by the condensation of cyano or nitro substituted ketones or aldehydes with epoxides, followed by the reduction of the cyano or nitro group to the NH group.

Noncyclic aminoacetals can be made by known methods for converting carbonyl compounds to the corresponding acetal or ketal, employing carbonyl compounds substituted with cyano or nitro groups and then effecting reduction of the groups to the -Nl-l group, and also be employing certain aminocarbonyl compounds directly. Also, aminoacetal and aminoketal compounds, both cyclic and noncyclic, can be made by amination of halo acetals, etc., the latter compounds being prepared by halogenation of carbonyl compounds prior to their conversion to the acetals or ketals by known methods. Wagner and Zook; Synthetic Organic Chemistry, PP 26l- 275, 1953, can be referred to for detailed description of various procedures for preparing various acetals and ketal starting materials employed in the present invention.

The xanthate starting materials can be prepared, for example, by reacting an alkali metal alkoxide with CS and then with methyl chloride. The reaction is represented by *To prepare the alkoxide of a tertiary alcohol a separate preliminary reaction with potassium metal is employed.

wherein R is the same as defined hereinbefore and K represents an alkali metal. Suitable alcohols include cyclohexanol, cyclohexenol, allyl alcohol, cinnamyl alcohol, crotyl alcohol, 2,3,5-trimethyl-3-hexanol; 2,3,4-trimethyl-2-hexanol and other like alcohols.

Both cyclic and noncyclic aminothioacetals and aminothioketals can be prepared in a manner similar to those previously described for the preparation of the cyclic and noncyclic aminoacetal and aminoketal compounds. A process for preparing dithiolane acids and esters is taught in US. Pat. No. 2,839,445. The so prepared compounds can be converted by methods known in the art to the corresponding nitriles or amides and the latter reduced to the amine intermediates which can then be reacted with suitable xanthate compounds to provide compounds within the scope of the present invention. One specific compound within the scope of the present invention is prepared in the following manner: To 13.6 grams of methyl ethyl xanthate is added 12.9 grams of 3,3-

with an alkylene oxide in an anhydrous solvent, and the resultbi rh l hi l amine, After the onta evolution of methyl mercaptan ceases the reaction mixture is heated at 60 C. under reduced pressure to'complete the removal of the mercaptan. The product, an oil. corresponding to the formula C;HS\ H H C-(CH w-\'C-O C;H

Qr sS is produced in substantially quantitative amounts.

Other aminoacetals which can be employed to prepared compounds within the scope of the present invention wherein A- corresponds to the radical I RS g 7 v are prepared in the following manner. An aldehyde compound corresponding to the formula wherein R is the sam e as defined hereinbefore, is reacted with a primary or secondary alcohol, ROH wherein R is the same as defined hereinbefore, and a dry hydrogen halide e.g. HCl, at ice temperature to form a compound corresponding to the for- This compound is reacted with RSNa to form the and this compound treated with hydrazine to give the aminoacetal starting material.

Other novel compounds which can be prepared by a method as defined hereinbefore and which are useful as flotation collectors in the concentration of sulfide compound containing ores include for example:

Various modifications may be made in the present invention without departing from the spirit or scope thereof for it is understood that we are limited only as defined in the appended claims.

What we claim is:

1. In the process of concentrating sulfide ores by froth flotation in the presence of a flotation collector compound the improvement which comprises: subjecting the sulfide ore in pulp form to a flotation collector comprising a compound corresponding to the formula wherein a. R is an alkylene group containing up to about 10 carbon atoms; wherein R is a member selected from the group consisting of an alkyl or alkenyl group containing up to 18 carbon atoms, a cycloalkyl or cycloalkenyl group containing up to about 8 carbon atoms, or an aralkyl or aralkenyl group wherein the alkyl or alkenyl portion contains up to about 5 carbon atoms and is bonded to Y. Y is a member selected from the group consisting of -S- or -O-; and d. A is a radical selected from the group consisting of a radical corresponding to the formula i. R is a member selected from the group consisting of H or an alkyl group containing up to about 7 carbon atoms; and

ii. when R is an alkyl group, X and X are both the same members selected from the group consisting of -S- or iii. when X and X are both -O- and R is an alkyl group containing up to about 7 carbon atoms, R and R are independently a member Self-fled from g p con- 4. The process as defined in claim 1 wherein said flotation sisting of an alkyl. alkenyl. cycloalkyl or cycloalkenyl group containing up to about 7 carbon atoms: collector corresponds to the formula iv. when X and X are both -S- and R is an alkyl group containing up to 7 carbon atoms, R and R are both the same member selected from the group consisting of alkyl, alkenyl, cycloalkyl. cycloalkenyl group containing up to about 7 carbon atoms;

v. when R is H. X and X are independently a member selected from the group consisting of -S- and -O and R and R are independently an alkyl, alkenyl, cycloalkyl or cycloalkenyl group containing up to about 7 carbon 5. The process as defined in claim 1 wherein said flotation 10 collector corresponds to the formula atoms; 3 (CzHsOhCHCHzOH CHM-O-SCH;

2. A is a radical corresponding to the formula 6. The process as defined in claim I wherein said flotation collector corresponds to the formula 1 1 1 s wherein W (CH5O) CHOH CH CH Nl :oCH CH;

X and X are independently a member selected from the group consisting of -0- or -S-; R and R' are independently a 7. The process 85 defined in claim 1 wherein said flotation member selected from the group consisting of H or an alkyl collector corresponds to the formula group containing up to about 5 carbon atoms, and R is a member selected from the group consisting of H or an alkyl group containing up to 7 carbon atoms. H S

2. The process as defined in claim 1 wherein from about (CH3O)2OHCH2CH2CH2I1I (U;' O06H 0.01 to about 0.25 pound of said compound per ton of sulfide ore pulp is employed.

3. The process as defined in claim 1 wherein said flotation 8. The process as defined in claim 1 wherein said flotation collector corresponds to the formula collector corresponds to the formula E S (C2H5O):CHCHgN( oCHCHZCH(C 3)2 (CHaO) CHCH CH CHN- SCH2CH; 

2. A is a radical corresponding to the formula
 2. The process as defined in claim 1 wherein from about 0.01 to about 0.25 pound of said compound per ton of sulfide ore pulp is employed.
 3. The process as defined in claim 1 wherein said flotation collector corresponds to the formula
 4. The process as defined in claim 1 wherein said flotation collector corresponds to the formula
 5. The process as defined in claim 1 wherein said flotation collector corresponds to the formula
 6. The process as defined in claim 1 wherein said flotation collector corresponds to the formula
 7. The process as defined in claim 1 wherein said flotation collector corresponds to the formula
 8. The process as defined in claim 1 wherein said flotation collector corresponds to the formula 